I had the following setup:
3) Installation of java commapi for windows.
Use of 'SerialPort' in SuperWabaSDK that in turn uses the commapi.
All indicates that what I did is correct: the virtual port is opened, etc. When opened, I can not open the port again in another windows program.
However, the java program stops when writing to the port. I tracked that using the Omniscient Debugger.
After many trials, I finally detected that another real port (my modem) works correctly with the port.
I have tried changing the settings of the virtual port, but that did not help.
The virtual port worked occasionally with the commapi, but that is difficult to repeat.
My windows version is XP Service Pack 2 and other patches (up-to-date).
I do not know what the problem is, but I guess that com0com is not behaving as the real port.